Process for finishing explosives powder.



.E. nu Pomp PROCESS FOR FINISHING EXPLOSIVEYPOWDER. APPLICATION FILED lULY 28, I9I5Q I. 1,240,549; PatentedSe t. 18,1917;

MENTGR frrzcm I a 2 I UNITED sTTEs PATENT OFFICE.

ERNEST. DU PONT, OF WILMINGTON, DELAWARE, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, T0 BALL GRAIN EXPLOSIVES COMPANY, OF WILMINGTON, DELA- WARE, -A CORPORATION OF DELAWARE. Y

jrnoo'nss FOR FINISHING EXPLOSI-VE POWDER.

To all whom it may concern: I

Be it known that I, ERNEST DU Form, a citizen of the United States, residing at Wilg nnugton, county of New Castle, and State of smoothing operation may be removed in order that the ished. k

A preferred construction of apparatus embodying my invention and adapted to carry out my process is shown in the accompanying drawings, in which The two rotary tubes (1 and 7) shown in the drawings are arranged so that the outlet of one communicates with the inlet of another. Each tube may be constructed in accordance with an, application filed of even date herewith by Francis I. du Pont, Serial No. 42266. Such construction is as follows: The inlet end 0 of each tube is annular, inclosing an opening into which extends the discharge end of a hopper d. Within the tube, near its inlet end, is a section of a spiral e, similar to a spiral conveyer. The spiral revolves with the tube in such a direction as to convey forwardly the material delivered by the chute (Z. Even though the level of powder in the tube back of the spiral is low, the effect of the spiral is'to grains niay be properly polfill the tube continuously to as much higher level as may be desired. The level to which the tube is filled is regulated by the diameter of the hole in the conical discharge end f.

Operating in conjunction with the tube a visan air-blast, 9 being a blower, h a chamber containing a steam coil through which the air from the blower passes, and i a pipe extending from the chamber to the outlet end of the tube a and through which the hot blast passes to the interior of the tube.

The tube (a is utilized for smoothing the grains of powder preparatory to polishing them. Theair blast through the tube is sullicieutly strong to iiiiii|ml\sl y blow out the dust which has been rubbed oil" in the to thoroughly dry the Specification of Letters Patent. Patented spt. 185 1917. Application filed July 28, 1915. Serial No. 42,261.

smoothing operation. The blast of air is heated in order. to prevent the moisture of the. air from moistening the powder and also because the polishing operation may be more successfully conducted when the powder is warm. 'The heated blast also is serviceable in case the drying operations may havefailed powder before'its introduction into the tubea;

The powder drops from the conical discharge'end of tube a into the hopper at the inlet end of tube 6. Thence the o'wder passes into the tube b, in which the pdlishing operation is conducted. Into the hopper is also fed, preferably continuously, a polishing material such as raphite. The graphite feeding device, whic Q a con--' ma be of n venient construction, is shown asa hopperm having at its bottom a roller 11 which revolves slowly and discharges the graphite,

the rate of discharge being proportionate,

to the speed of the roller. To insure the proper working ofa feeder, there is provided a spider 0 which slowly revolves in the hopper and prevents the graphite from arching across.

From the above description it will be un-' derstood that the powder to be glazed travels continuously through the rotating tube a,

which smooths the grains, the dust resulting from this operation being removed by an air blast, and that the powder together with a polishing material, thence passes into and travels continuously through the rotating tube 6, which is not provided with an air blast and which, by the motion of the powder and 'polishinginaterial one uponthe other, polishes the grains,

Having now fully described my invention, what I-elaim and desire to protect by Letters Patent is:

1. In the process of finishing explosive granular powder, causing the powder grains to have a combined longitudinal and transverse rolling movement and continuously applying anddischarg ng powder at 0pp0" site ends of the movlng stream so as to maintain substantially constant the volume of powder being treated and at the same time carry on the operation continuously.

2. In the process offinishing explosive granular powder], causing the same to have a combined l ngitudinal and transverse rollingmovenie smooth them, and at the same time passing a current of air over the moving stream of grains in a direction opposite to their longitudinal direction of movement to remove the dust created by the smoothing operation. 7 Y

3. In the process of finishing explosive granular powder, causing the powder grains, together with a polishing material, to have a combined longitudinal and transverse rolling movement, whereby the powder is polished in a continuous manner.

4. In the process of finishing explosive granular powder, causing the same to have a combined longitudinal and transverse rolling movement to smooth them, and at the same time passing a current of air over the moving stream of grains in a direction opposite to their longitudinal direction ofmovement to remove the dust created by the smoothing operation, and continuously supplying and discharging powder at opposite ends of the moving stream so as to maintain substantially constant the volume of powder being treated and at-the same'time carry on the smoothing operation continu ously.

5. In the process of finishing explosive granular powder, causing the powder grains, together with a polishing material, to have a combinedlongitudinal and transverse rolling movement, and continuously supply and discharge powder grains and polishing material at opposite ends so as to maintain substantially constant the volume of powder being treated and at the same time carry on the polishing operation continuously.

6. The process of finishing explosive granular powder which consists in imparting to the same a continuous forward movement, introducing into the continuous stream of moving powder a polishing material, and causing the powder, both back of and be yond the point of introduction of the polishing material to have also a transverse rolling movement, thereby, in a continuous manner, first smoothing and then polishing the grains.

7 The process of finishing explosive granular powder which consists in imparting to the same a continuous forward movement, introducing unto the continuous stream of moving powder. a polishing material, and causing the powder, both back of and beyond the point of introduction of the polishing material to have also a transverse r011- ing movement, and directing a blast of artificially heated air over that part of the stream of powder back of the point of introduction of the polishing material in a direction opposite to the direction of forward travel of the powder, thereby, in a continuous manner, first smoothing the grains and blowing away the dust created in the smoothing operation and then polishing the grains.

In testimony of which invention, I have hereunto Set my hand, at Philadelphia, on this 27th day of July, 1915.

ERNEST DU PONT.

Witnesses:'

M. M. HAMILTON, E. E. WALL. 

